In traditional astrology there has been the long idea of the 'final depositor' of a birth chart that then means that it operates like a 'bottom line' or 'foundation' upon which to understand and view the rest of the birth chart: that it conditions all other archetypes relative to that final depositor. In the chain you presented you will notice that the final depositor would be Jupiter: Venus/Cap/3rd - Saturn/Sag/2nd - Jupiter/Libra/12th. Venus is ruled by Saturn and that Saturn is ruled by Jupiter.

Almost all charts have one or two planets that the rest of the birth chart comes too. In EA terms the obvious question is 'why' where the why correlates to the evolutionary necessity of having whatever planet(s) as the final depositor in the birth chart.